Electrostatic chuck and plasma processing apparatus

ABSTRACT

An electrostatic chuck of an embodiment includes a base, a dielectric layer, and a chuck main body. The dielectric layer is provided on the base, and is fixed to the base. The chuck main body is mounted on the dielectric layer. The chuck main body has a ceramic main body, a first electrode, a second electrode, and a third electrode. The ceramic main body has a substrate mounting region. The first electrode is provided in the substrate mounting region. The second electrode and the third electrode form a bipolar electrode. The second electrode and the third electrode are provided in the ceramic main body, and are provided between the first electrode and the dielectric layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of priority fromJapanese Patent Application No. 2017-106728 filed on May 30, 2017, theentire contents of which are incorporated herein by reference.

FIELD

Exemplary embodiment of the present disclosure relate to anelectrostatic chuck and a plasma processing apparatus.

BACKGROUND

In manufacturing of electronic devices, a plasma processing apparatus isused to perform processing on a substrate. The plasma processingapparatus generally includes a chamber body that provides a chamber andan electrostatic chuck provided in the chamber.

The electrostatic chuck has a function of holding a substrate, and afunction of adjusting the temperature of the substrate. Theelectrostatic chuck has a base and a chuck main body. A flow channel fora heat exchange medium (for example, a refrigerant) is formed in thebase. The chuck main body has a ceramic main body and a film-shapedelectrode provided in the ceramic main body. A DC power supply iselectrically connected to the electrode of the chuck main body. Asubstrate is placed on the chuck main body. In a case where a voltagefrom the DC power supply is applied to the electrode of the chuck mainbody, an electrostatic attractive force is generated between the chuckmain body and the substrate. Due to the generated electrostaticattractive force, the substrate is attracted to the chuck main body andheld on the chuck main body. In addition, by supplying the heat exchangemedium to the base, heat exchange is performed between the base and thechuck main body, the temperature of the chuck main body is adjusted, andthe temperature of the substrate is adjusted. The chuck main body isbonded onto the base with an adhesive. The plasma processing apparatushaving such a stage is disclosed, for example, in Japanese PatentApplication Laid-Open Publication No. 2015-162618.

SUMMARY

According to an aspect, there is provided an electrostatic chuck. Theelectrostatic chuck according to the aspect includes a base, adielectric layer, and a chuck main body. A flow channel for a heatexchange medium is provided in the base. The dielectric layer isprovided on the base, and is fixed to the base. The chuck main body ismounted on the dielectric layer. The chuck main body is configured tohold a substrate placed thereon with an electrostatic attractive force.The chuck main body has a ceramic main body, a first electrode, a secondelectrode, and a third electrode. The ceramic main body has a substratemounting region. The first electrode is provided in the substratemounting region in order to generate an electrostatic attractive forcebetween a substrate mounted on the substrate mounting region and thechuck main body. The second electrode and the third electrode form abipolar electrode. The second electrode and the third electrode areprovided in the ceramic main body and are provided between the firstelectrode and the dielectric layer in order to generate an electrostaticattractive force between the chuck main body and the dielectric layer.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, exemplaryembodiments, and features described above, further aspects, exemplaryembodiments, and features will become apparent by reference to thedrawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a plasma processing apparatus accordingto an exemplary embodiment.

FIG. 2 is a cross-sectional view of an electrostatic chuck according toa first exemplary embodiment.

FIGS. 3A, 3B, and 3C are cross-sectional views of an exemplarydielectric layer.

FIG. 4 is a cross-sectional view of an exemplary electrostatic chuck ina portion including an outer peripheral region of an chuck main bodythereof.

FIG. 5 illustrates second to fifth electrodes of the electrostatic chuckaccording to the first exemplary embodiment.

FIG. 6 is a plan view showing another example of the fourth electrodeand the fifth electrode.

FIG. 7 is a plan view showing an example of the back surface of thechuck main body.

FIG. 8 is a cross-sectional view of an electrostatic chuck according toa second exemplary embodiment.

FIG. 9 is a cross-sectional view of an electrostatic chuck according toa third exemplary embodiment.

FIG. 10 illustrates the second and third electrodes of the electrostaticchuck according to the third embodiment.

FIG. 11 is a flowchart showing a method of operating an electrostaticchuck of a plasma processing apparatus according to an exemplaryembodiment.

FIG. 12 is a flowchart showing the method of operating an electrostaticchuck of a plasma processing apparatus according to the exemplaryembodiment.

FIG. 13 is an exemplary timing chart relevant to the method shown inFIGS. 11 and 12.

FIG. 14 is an exemplary timing chart relevant to the method shown inFIGS. 11 and 12.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. The exemplaryembodiments described in the detailed description, drawing, and claimsare not meant to be limiting. Other exemplary embodiments may beutilized, and other changes may be made, without departing from thespirit or scope of the subject matter presented here.

In the plasma processing performed in the plasma processing apparatus,the temperature of the substrate placed on the chuck main body may beset to a low temperature. In order to set the temperature of thesubstrate to a low temperature, a refrigerant is supplied to the base asa heat exchange medium.

In a case where the temperature of the base is set to a temperatureequal to or less than the glass transition point of the adhesive, theadhesive hardens to lose flexibility. In a case where the flexibility ofthe adhesive is lost, the chuck main body may be peeled off from thebase or cracking may occur in the chuck main body due to the differencebetween the linear expansion coefficient of the base and the linearexpansion coefficient of the chuck main body. That is, the electrostaticchuck may be damaged. Even if the difference between the linearexpansion coefficient of the base and the linear expansion coefficientof the chuck main body is small, in a case where the difference betweenthe temperature of the electrostatic chuck at the time of use thereofand the temperature in a case where the chuck main body is bonded to thebase is large, warpage may occur in the electrostatic chuck and theelectrostatic chuck may not be able to hold the substrate. That is,malfunction of the electrostatic chuck may occur. Therefore, it isrequired to enable the chuck main body to be fixed to the base withoutusing an adhesive.

According to an aspect, there is provided an electrostatic chuck. Theelectrostatic chuck according to the aspect includes a base, adielectric layer, and a chuck main body. A flow channel for a heatexchange medium is provided in the base. The dielectric layer isprovided on the base, and is fixed to the base. The chuck main body ismounted on the dielectric layer. The chuck main body is configured tohold a substrate placed thereon with an electrostatic attractive force.The chuck main body has a ceramic main body, a first electrode, a secondelectrode, and a third electrode. The ceramic main body has a substratemounting region. The first electrode is provided in the substratemounting region in order to generate an electrostatic attractive forcebetween a substrate mounted on the substrate mounting region and thechuck main body. The second electrode and the third electrode form abipolar electrode. The second electrode and the third electrode areprovided in the ceramic main body and are provided between the firstelectrode and the dielectric layer in order to generate an electrostaticattractive force between the chuck main body and the dielectric layer.

In the electrostatic chuck according to the aspect, by applying avoltage to the first electrode during plasma generation, anelectrostatic attractive force is generated between the chuck main bodyand the substrate that receives electric charges from the plasma. Due tothe generated electrostatic attractive force, the substrate is held onthe chuck main body. In addition, an electrostatic attractive force isgenerated between the chuck main body and the dielectric layer evenwithout a plasma by applying voltages with opposite polarities to thesecond electrode and the third electrode. Due to the generatedelectrostatic attractive force, the chuck main body is attracted to thedielectric layer, fixed to the dielectric layer, and fixed to the basevia the dielectric layer. Therefore, according to the electrostaticchuck, it is possible to fix the chuck main body to the base at anarbitrary timing without using an adhesive. In a case where atemperature difference occurs between the base and the chuck main body,the chuck main body can be fixed to the base via the dielectric layer bythe electrostatic attractive force, after the temperature differencebetween the temperature of the base and the temperature of the chuckmain body is reduced. Therefore, it is possible to suppress the peelingof the chuck main body and the cracking of the chuck main body. Inaddition, it is possible to suppress the warpage of the electrostaticchuck.

In an embodiment, the ceramic main body may further provide an outerperipheral region which surrounds the substrate mounting region, and onwhich a focus ring is placed.

In an embodiment, the chuck main body may further include a fourthelectrode and a fifth electrode that form a bipolar electrode. Thefourth electrode and the fifth electrode may be provided in the outerperipheral region to generate an electrostatic attractive force betweenthe focus ring and the chuck main body. In the embodiment, anelectrostatic attractive force is generated between the outer peripheralregion and the focus ring even without a plasma by applying voltageswith opposite polarities to the fourth electrode and the fifthelectrode. Due to the generated electrostatic attractive force, thefocus ring is held in the outer peripheral region of the chuck mainbody.

In an embodiment, the fourth electrode and the fifth electrode may befarther from the dielectric layer than the second electrode and thethird electrode. In another embodiment, the second electrode, the thirdelectrode, the fourth electrode, and the fifth electrode may be providedalong the same plane.

In an embodiment, the second electrode and the third electrode may beprovided across the substrate mounting region and the outer peripheralregion. In the embodiment, an electrostatic attractive force isgenerated between the outer peripheral region and the focus ring byapplying voltages with opposite polarities to the second electrode andthe third electrode. Due to the generated electrostatic attractiveforce, the focus ring is held in the outer peripheral region of thechuck main body.

In an embodiment, a first flow channel that is opened on a surface ofthe outer peripheral region on a side opposite to a side of thedielectric layer may be formed in the base, the dielectric layer, andthe chuck main body. In the embodiment, even if the focus ring isattracted to the outer peripheral region of the chuck main body due toresidual charges or the like, the focus ring can be detached from theouter peripheral region of the chuck main body by supplying gas to thefirst flow channel.

In an embodiment, the dielectric layer may be a ceramic sprayed film. Inanother embodiment, the dielectric layer may be a resin layer bondeddirectly to the base or bonded to the base with an adhesive layerinterposed therebetween.

In an embodiment, a groove may be provided on a surface of the chuckmain body on a side of the dielectric layer or a surface of thedielectric layer on a side of the chuck main body, and a second flowchannel connected to the groove may be formed in the base and thedielectric layer. In the embodiment, even if the chuck main body isattracted to the dielectric layer due to residual charges or the like,the chuck main body can be detached from the dielectric layer bysupplying gas to the second flow channel.

In an embodiment, the electrostatic chuck may further include a firsttemperature sensor configured to measure a temperature of the base and asecond temperature sensor configured to measure a temperature of thechuck main body.

According to another aspect, there is provided a plasma processingapparatus. The plasma processing apparatus includes a chamber main body,the electrostatic chuck according to any one of the above aspect and thevarious embodiments, a radio frequency power supply, and first to thirdDC power supplies. The chamber main body provides a chamber. The radiofrequency power supply is electrically connected to the base of theelectrostatic chuck. The first DC power supply is electrically connectedto the first electrode. The second DC power supply is electricallyconnected to the second electrode. The third DC power supply iselectrically connected to the third electrode.

In an embodiment, the plasma processing apparatus may further include afourth DC power supply electrically connected to the fourth electrode ofthe electrostatic chuck and a fifth DC power supply electricallyconnected to the fifth electrode of the electrostatic chuck.

In an embodiment, the plasma processing apparatus may further include afirst gas supply unit and a first exhaust device that are selectivelyconnected to the first flow channel of the electrostatic chuck.

In an embodiment, the plasma processing apparatus may further include asecond gas supply unit and a second exhaust device that are selectivelyconnected to the second flow channel of the electrostatic chuck.

Hereinafter, various embodiments will be described in detail withreference to the drawings. In the drawing, the same or equivalentportions are denoted by the same reference symbols.

FIG. 1 schematically illustrates a plasma processing apparatus accordingto an exemplary embodiment. FIG. 1 schematically illustrates a structurein a longitudinal section of a plasma processing apparatus 10 accordingto the exemplary embodiment. The plasma processing apparatus 10 shown inFIG. 1 is a capacitively coupled plasma processing apparatus.

The plasma processing apparatus 10 includes a chamber body 12. Thechamber body 12 has an approximately cylindrical shape. The chamber body12 provides its internal space as a chamber 12 c. The chamber body 12 isformed of, for example, aluminum. The chamber body 12 is connected tothe ground potential. A film having plasma resistance is formed on theinner wall surface of the chamber body 12, that is, a wall surfacedefining a chamber 12 c. The film may be a film formed by an anodicoxidation treatment or a ceramic film, such as a film formed of yttriumoxide. A passage 12 g is formed in a side wall of the chamber body 12.In a case where a substrate W is transferred into the chamber 12 c and acase where the substrate W is transferred out from the chamber 12 c, thesubstrate W passes through the passage 12 g. A gate valve 14 is attachedto the side wall of the chamber body 12. The passage 12 g can be openedand closed by the gate valve 14.

In the chamber 12 c, a support portion 15 extends upward from the bottomportion of the chamber body 12. The support portion 15 has anapproximately cylindrical shape, and is formed of an insulatingmaterial, such as quartz. A stage 16 is mounted on the support portion15, and the stage 16 is supported by the support portion 15. The stage16 is configured to support the substrate W in the chamber 12 c. Thestage 16 includes an electrode plate 18 and an electrostatic chuck 20.The electrode plate 18 has conductivity, and has an approximately discshape. The electrode plate 18 is formed of, for example, aluminum. Theelectrostatic chuck 20 is provided on the electrode plate 18. Theelectrostatic chuck 20 includes a base 22, a dielectric layer 24, and achuck main body 26. The base 22 has conductivity, and forms a lowerelectrode. The base 22 is provided on the electrode plate 18, and iselectrically connected to the electrode plate 18.

In the base 22, a flow channel 22 f is provided. The flow channel 22 fis a flow channel for a heat exchange medium. As the heat exchangemedium, a liquid refrigerant or a refrigerant (for example, Freon) forcooling the base 22 by its vaporization is used. The heat exchangemedium is supplied to the flow channel 22 f from a chiller unit providedoutside the chamber body 12 through a pipe 23 a. The heat exchangemedium supplied to the flow channel 22 f is returned to the chiller unitthrough a pipe 23 b. In this manner, the heat exchange medium issupplied to the flow channel 22 f to circulate between the flow channel22 f and the chiller unit.

A gas supply line 25 is provided in the plasma processing apparatus 10.The gas supply line 25 supplies a heat transfer gas from a gas supplymechanism, for example, helium gas, between the upper surface of thechuck main body 26 and the back surface (bottom surface) of thesubstrate W.

A cylindrical portion 28 extends upward from the bottom portion of thechamber body 12. The cylindrical portion 28 extends along the outerperiphery of the support portion 15. The cylindrical portion 28 hasconductivity, and has an approximately cylindrical shape. Thecylindrical portion 28 is connected to the ground potential. Aninsulating portion 29 is provided on the cylindrical portion 28. Theinsulating portion 29 has an insulation property, and is formed ofceramic, such as quartz. The insulating portion 29 has an approximatelycylindrical shape, and extends along the outer periphery of theelectrode plate 18 and the outer periphery of the electrostatic chuck20. A focus ring FR is mounted on the outer peripheral region of thechuck main body 26 of the electrostatic chuck 20. The focus ring FR hasan approximately annular plate shape, and is formed of, for example,silicon or silicon carbide (SiC). The focus ring FR is provided so as tosurround the edge of a substrate mounting region of the chuck main body26 and the edge of the substrate W.

The plasma processing apparatus 10 further includes an upper electrode30. The upper electrode 30 is provided above the stage 16. The upperelectrode 30 closes an upper opening of the chamber body 12 togetherwith a member 32. The member 32 has an insulation property. The upperelectrode 30 is supported by the upper portion of the chamber body 12 bythe member 32.

The upper electrode 30 includes a top plate 34 and a support body 36.The bottom surface of the top plate 34 defines the chamber 12 c. Aplurality of gas delivery holes 34 a are provided in the top plate 34.Each of the plurality of gas delivery holes 34 a penetrates the topplate 34 in the plate thickness direction (vertical direction). The topplate 34 is formed of, for example, silicon, although the material isnot limited thereto. Alternatively, the top plate 34 may have astructure in which a plasma resistant film is provided on the surface ofa base material formed of aluminum. The film may be a film formed by ananodic oxidation treatment or a ceramic film, such as a film formed ofyttrium oxide.

The support body 36 is a component that detachably supports the topplate 34. The support body 36 can be formed of a conductive material,for example, aluminum. A gas diffusion chamber 36 a is provided insidethe support body 36. A plurality of gas holes 36 b extend downward fromthe gas diffusion chamber 36 a. The plurality of gas holes 36 bcommunicate with the plurality of gas delivery holes 34 a, respectively.A gas introduction port 36 c for introducing a gas to the gas diffusionchamber 36 a is formed in the support body 36, and a gas supply pipe 38is connected to the gas introduction port 36 c.

A gas source group 40 is connected to the gas supply pipe 38 through avalve group 42 and a flow rate controller group 44. The gas source group40 includes a plurality of gas sources. The valve group 42 includes aplurality of valves, and the flow rate controller group 44 includes aplurality of flow rate controllers. Each of the plurality of flow ratecontrollers of the flow rate controller group 44 is a mass flowcontroller or a pressure control type flow rate controller. Each of theplurality of gas sources of the gas source group 40 is connected to thegas supply pipe 38 through a corresponding valve of the valve group 42and a corresponding flow rate controller of the flow rate controllergroup 44. The plasma processing apparatus 10 can supply a gas from oneor more gas sources, which are selected from the plurality of gassources of the gas source group 40, to the chamber 12 c at theindividually adjusted flow rate.

A baffle plate 48 is provided between the cylindrical portion 28 and theside wall of the chamber body 12. The baffle plate 48 can be formed, forexample, by coating ceramic, such as yttrium oxide, on an aluminum basematerial. A number of through holes are formed in the baffle plate 48.Below the baffle plate 48, an exhaust pipe 52 is connected to the bottomportion of the chamber body 12. An exhaust device 50 is connected to theexhaust pipe 52. The exhaust device 50 includes a pressure controller,such as an automatic pressure control valve, and a vacuum pump, such asa turbo molecular pump, and can depressurize the chamber 12 c.

The plasma processing apparatus 10 further includes a first radiofrequency power supply 62. The first radio frequency power supply 62 isa power supply for generating a first radio frequency wave for plasmageneration. The first radio frequency wave has a frequency within arange of 27 to 100 MHz, for example, 60 MHz. The first radio frequencypower supply 62 is connected to the upper electrode 30 through amatching unit 63. The matching unit 63 has a circuit for matching theoutput impedance of the first radio frequency power supply 62 and theimpedance on the load side (upper electrode 30 side). The first radiofrequency power supply 62 may be connected to the electrode plate 18through the matching unit 63. In a case where the first radio frequencypower supply 62 is connected to the electrode plate 18, the upperelectrode 30 is connected to the ground potential.

The plasma processing apparatus 10 further includes a second radiofrequency power supply 64. The second radio frequency power supply 64 isa power supply for generating a second radio frequency wave for bias forattracting ions to the substrate W. The second radio frequency is lowerthan the first radio frequency. The second radio frequency wave has afrequency within a range of 400 kHz to 13.56 MHz, for example, 400 kHz.The second radio frequency power supply 64 is connected to the electrodeplate 18 through a matching unit 65. The matching unit 65 has a circuitfor matching the output impedance of the second radio frequency powersupply 64 and the impedance on the load side (electrode plate 18 side).

In an embodiment, the plasma processing apparatus 10 may further includea controller Cnt. The controller Cnt is a computer including aprocessor, a storage device, an input device, a display device, and thelike, and controls each unit of the plasma processing apparatus 10.Specifically, the controller Cnt executes a control program stored inthe storage device, and controls each unit of the plasma processingapparatus 10 based on recipe data stored in the storage device. As aresult, the plasma processing apparatus 10 executes the processdesignated by the recipe data.

Hereinafter, electrostatic chucks of some embodiments that can beadopted as the electrostatic chuck 20 will be described.

Electrostatic Chuck of a First Exemplary Embodiment

FIG. 2 is a cross-sectional view of an electrostatic chuck according toa first exemplary embodiment. An electrostatic chuck 20A shown in FIG. 2can be used as the electrostatic chuck 20 of the plasma processingapparatus 10. The electrostatic chuck 20A has the base 22 and thedielectric layer 24. The electrostatic chuck 20A has a chuck main body26A as the chuck main body 26.

The base 22 has conductivity, and has an approximately disc shape. Thebase 22 is formed of, for example, aluminum. The base 22 is provided onthe electrode plate 18. The base 22 is electrically connected to theelectrode plate 18. The base 22 forms a lower electrode, and a radiofrequency wave (a second radio frequency wave or a first radio frequencywave and a second radio frequency wave) is supplied to the base 22through the electrode plate 18. The flow channel 22 f described above isformed inside the base 22. The flow channel 22 f extends, for example,in a spiral shape in the base 22.

The dielectric layer 24 is provided on the base 22, and is fixed to thebase 22. The dielectric layer 24 is formed of a dielectric material.FIGS. 3A, 3B, and 3C are cross-sectional views of an exemplarydielectric layer. A dielectric layer 24A shown in FIG. 3A, a dielectriclayer 24B shown in FIG. 3B, and a dielectric layer 24C shown in FIG. 3Ccan be adopted as the dielectric layer 24.

The dielectric layer 24A is a film formed of ceramic, for example,aluminum oxide, or yttrium oxide, and is provided on the upper surfaceof the base 22. The dielectric layer 24A is formed, for example, bythermal spraying of ceramic onto the upper surface of the base 22. Thedielectric layer 24B has an adhesive layer 241 and a resin layer 242.The resin layer 242 is fixed to the upper surface of the base 22 by theadhesive layer 241. The resin layer 242 is formed of, for example,polyimide. The dielectric layer 24C is a resin film. The dielectriclayer 24C is directly bonded to the upper surface of the base 22. Thedielectric layer 24C is bonded to the upper surface of the base 22 by alaser or bonded to the upper surface of the base 22 by using an anchoreffect. The dielectric layer 24C is formed of, for example,fluorine-based resin.

The thickness of the dielectric layer 24, such as the dielectric layer24A, 24B, or 24C is 50 μm or more and 500 μm or less. The dielectriclayer 24 having such a thickness can follow deformation of the base 22due to heat. In order to promote heat exchange between the base 22 andthe chuck main body 26, the thickness of the dielectric layer 24 is setso as to have a thermal resistance of a predetermined value or less. Thethermal resistance is defined as a value obtained by dividing thethickness of the dielectric layer 24 by the thermal conductivity of thedielectric layer 24.

Referring to FIG. 2 again, the chuck main body 26A is mounted on thedielectric layer 24. The chuck main body 26A is configured to hold asubstrate W placed thereon with an electrostatic attractive force. Theelectrostatic attractive force is a Coulomb force or a Johnsen-Rahbekforce. The chuck main body 26A includes a ceramic main body 260, a firstelectrode 261, a second electrode 262, a third electrode 263, a fourthelectrode 264, and a fifth electrode 265.

The ceramic main body 260 has an approximately disc shape. The ceramicmain body 260 has a substrate mounting region 260 a and an outerperipheral region 260 b. The substrate mounting region 260 a is a regionon which the substrate W is placed. The substrate mounting region 260 ahas an approximately disc shape. The outer peripheral region 260 b is anapproximately annular plate shaped region, and extends so as to surroundthe substrate mounting region 260 a. The back surface (surface on thedielectric layer 24 side) of the substrate mounting region 260 a and theback surface (surface on the dielectric layer 24 side) of the outerperipheral region 260 b form a continuous flat back surface (bottomsurface) of the ceramic main body 260, that is, the back surface of thechuck main body 26A. On the other hand, the upper surface of the outerperipheral region 260 b extends closer to the back surface of the chuckmain body 26A than the upper surface of the substrate mounting region260 a. On the outer peripheral region 260 b, the focus ring FR ismounted so as to surround the edge of the substrate mounting region 260a and the edge of the substrate W.

FIG. 4 is a cross-sectional view of an exemplary electrostatic chuck ina portion including an outer peripheral region of an chuck main bodythereof. As shown in FIG. 4, in an embodiment, a flow channel 20 f(first flow channel) opened on the surface (upper surface) of the outerperipheral region 260 b on a side opposite to the dielectric layer 24 isformed in the outer peripheral region 260 b of the chuck main body 26A,the dielectric layer 24, the base 22, and the electrode plate 18. Theflow channel 20 f is provided by an insulating pipe 70 inside theelectrode plate 18 and the base 22. A gas supply unit 71 (first gassupply unit) and an exhaust device 72 (first exhaust device) areselectively connected to the flow channel 20 f. The gas supply unit 71supplies gas to the back surface (bottom surface) of the focus ring FRthrough the flow channel 20 f. The exhaust device 72 vacuums the backsurface of the focus ring FR through the flow channel 20 f.

Referring to FIG. 2 again, the first electrode 261 is provided in thesubstrate mounting region 260 a. The first electrode 261 is afilm-shaped electrode. The first electrode 261 is connected to a DCpower supply DS1 (first DC power supply) through a switch SW1. The DCpower supply DS1 generates a DC voltage applied to the first electrode261. In a case where a DC voltage from the DC power supply DS1 isapplied to the first electrode 261 during plasma generation, anelectrostatic attractive force is generated between the chuck main body26A and the substrate W that receives charges from the plasma. Due tothe generated electrostatic attractive force, the substrate W isattracted to the chuck main body 26A and fixed to the chuck main body26A.

Hereinafter, FIG. 5 will be referred to together with FIG. 2. FIG. 5illustrates the second to fifth electrodes of the electrostatic chuckaccording to the first exemplary embodiment. In FIG. 5, the second tofifth electrodes are shown at the same horizontal level for the sake ofconvenience. However, in the electrostatic chuck 20A, the fourthelectrode 264 and the fifth electrode 265 are formed above the secondelectrode 262 and the third electrode 263.

As shown in FIGS. 2 and 5, the second electrode 262 and the thirdelectrode 263 are provided in the substrate mounting region 260 a of theceramic main body 260. The second electrode 262 and the third electrode263 form a bipolar electrode. The fourth electrode 264 and the fifthelectrode 265 are provided in the outer peripheral region 260 b. Thefourth electrode 264 and the fifth electrode 265 form a bipolarelectrode. The fourth electrode 264 and the fifth electrode 265 arefarther from the dielectric layer 24 than the second electrode 262 andthe third electrode 263. In other words, the second electrode 262 andthe third electrode 263 are provided closer to the dielectric layer 24in the ceramic main body 260 than the fourth electrode 264 and the fifthelectrode 265, that is, close to the back surface of the ceramic mainbody 260.

The second electrode 262 and the third electrode 263 are film-shapedelectrodes, and have comb-tooth shapes as shown in FIG. 5. The secondelectrode 262 and the third electrode 263 are provided so that theircomb teeth are alternately arranged along one direction. The fourthelectrode 264 and the fifth electrode 265 are film-shaped electrodes,and have concentric ring shapes as shown in FIG. 5. FIG. 6 is a planview showing another example of the fourth electrode and the fifthelectrode. As shown in FIG. 6, the fourth electrode 264 and the fifthelectrode 265 may have comb teeth shapes, and may be provided so thattheir comb teeth are alternately arranged along the circumferentialdirection.

Referring to FIG. 2 again, a DC power supply DS2 (second DC powersupply) is electrically connected to the second electrode 262 through aswitch SW2. A DC power supply DS3 (third DC power supply) iselectrically connected to the third electrode 263 through a switch SW3.A DC power supply DS4 (fourth DC power supply) is electrically connectedto the fourth electrode 264 through a switch SW4. A DC power supply DS5(fifth DC power supply) is electrically connected to the fifth electrode265 through a switch SW5.

The DC power supply DS2 generates a voltage applied to the secondelectrode 262. The DC power supply DS3 generates a voltage applied tothe third electrode 263. The voltage applied from the DC power supplyDS2 to the second electrode 262 and the voltage applied from the DCpower supply DS3 to the third electrode 263 have opposite polarities. Ina case where a voltage is applied from the DC power supply DS2 to thesecond electrode 262 and a voltage is applied from the DC power supplyDS3 to the third electrode 263, an electrostatic attractive force isgenerated between the chuck main body 26A and the dielectric layer 24.Due to the generated electrostatic attractive force, the chuck main body26A is attracted to the dielectric layer 24. By applying a voltage fromthe DC power supply DS2 to the second electrode 262 and applying avoltage from the DC power supply DS3 to the third electrode 263, it ispossible to generate an electrostatic attractive force between the chuckmain body 26A and the dielectric layer 24 even without a plasma, thatis, even in a state in which no plasma is generated. Therefore, it ispossible to attract the chuck main body 26A to the dielectric layer 24at an arbitrary timing.

The DC power supply DS4 generates a voltage applied to the fourthelectrode 264. The DC power supply DS5 generates a voltage applied tothe fifth electrode 265. The voltage applied from the DC power supplyDS4 to the fourth electrode 264 and the voltage applied from the DCpower supply DS5 to the fifth electrode 265 have opposite polarities. Ina case where a voltage is applied from the DC power supply DS4 to thefourth electrode 264 and a voltage is applied from the DC power supplyDS5 to the fifth electrode 265, an electrostatic attractive force isgenerated between the chuck main body 26A and the focus ring FR. Due tothe generated electrostatic attractive force, the focus ring FR isattracted to the chuck main body 26A and fixed to the chuck main body26A. By applying a voltage from the DC power supply DS4 to the fourthelectrode 264 and applying a voltage from the DC power supply DS5 to thefifth electrode 265, it is possible to generate an electrostaticattractive force between the chuck main body 26A and the focus ring FReven without a plasma, that is, even in a state in which no plasma isgenerated. Therefore, it is possible to attract the focus ring FR to thechuck main body 26A at an arbitrary timing.

FIG. 7 is a plan view showing an example of the back surface of thechuck main body. As shown in FIGS. 2 and 7, the back surface of thechuck main body 26A, that is, the back surface of the ceramic main body260 provides a groove 260 g. In one example, the groove 260 g extendsalong a plurality of concentric circles and a plurality of line segmentsextending radially from the center of the concentric circles. In thedielectric layer 24, the base 22, and the electrode plate 18, a flowchannel 20 g (second flow channel) connected to the groove 260 g isformed. At least a part of the flow channel 20 g is provided by a pipe.A gas supply unit 73 (second gas supply unit) and an exhaust device 74(second exhaust device) are selectively connected to the flow channel 20g. The gas supply unit 73 supplies gas to the groove 260 g through theflow channel 20 g. The exhaust device 74 vacuums the back surface of thechuck main body 26A through the flow channel 20 g and the groove 260 g.The groove 260 g may be formed on the surface of the dielectric layer 24on a side of the chuck main body 26A.

As shown in FIG. 2, a temperature sensor 76 and a temperature sensor 77are provided in the electrostatic chuck 20A. The temperature sensor 76(second temperature sensor) is configured to measure the temperature ofthe chuck main body 26A. The temperature sensor 76 may be anytemperature sensor, such as a fluorescent thermometer or a thermocouple.The temperature measurement value of the chuck main body 26A measured bythe temperature sensor 76 is transmitted to the controller Cnt. Thetemperature sensor 77 (first temperature sensor) is configured tomeasure the temperature of the base 22. The temperature sensor 77 may beany temperature sensor, such as a fluorescent thermometer or athermocouple. The temperature measurement value of the base 22 measuredby the temperature sensor 77 is transmitted to the controller Cnt.

Electrostatic Chuck of a Second Exemplary Embodiment

FIG. 8 is a cross-sectional view of an electrostatic chuck according toa second exemplary embodiment. An electrostatic chuck 20B of the secondembodiment shown in FIG. 8 can be used as the electrostatic chuck 20 ofthe plasma processing apparatus 10. The electrostatic chuck 20B has achuck main body 26B instead of the chuck main body 26A. The chuck mainbody 26B is different from the chuck main body 26A in terms of theposition of the electrode in the ceramic main body 260. In the ceramicmain body 260 of the chuck main body 26B, the second electrode 262, thethird electrode 263, the fourth electrode 264, and the fifth electrode265 are formed along the same plane. That is, a distance from the secondelectrode 262 to the back surface of the ceramic main body 260, adistance from the third electrode 263 to the back surface of the ceramicmain body 260, a distance from the fourth electrode 264 to the backsurface of the ceramic main body 260, and a distance from the fifthelectrode 265 to the back surface of the ceramic main body 260 are thesame. In other respects, the electrostatic chuck 20B has the sameconfiguration as the electrostatic chuck 20A.

Electrostatic Chuck of a Third Exemplary Embodiment

FIG. 9 is a cross-sectional view of an electrostatic chuck according toa third exemplary embodiment. An electrostatic chuck 20C of the thirdexemplary embodiment shown in FIG. 9 can be used as the electrostaticchuck 20 of the plasma processing apparatus 10. Hereinafter, how theelectrostatic chuck 20C is different from the electrostatic chuck 20Aand the electrostatic chuck 20B will be described. The electrostaticchuck 20C has a chuck main body 26C instead of the chuck main body 26Aand the chuck main body 26B. The chuck main body 26C does not have thefourth electrode and the fifth electrode. In the ceramic main body 260of the chuck main body 26C, the first electrode 261, the secondelectrode 262, and the third electrode 263 are provided.

FIG. 10 illustrates the second and third electrodes of the electrostaticchuck according to the third embodiment. As shown in FIGS. 9 and 10, inthe chuck main body 26C, the second electrode 262 and the thirdelectrode 263 are film-shaped electrodes, and extend spirally in theceramic main body 260. In the chuck main body 26C, the second electrode262 and the third electrode 263 are provided along the same plane. Inthe chuck main body 26C, the second electrode 262 and the thirdelectrode 263 are provided across the substrate mounting region 260 aand the outer peripheral region 260 b.

According to the electrostatic chuck 20C, by applying voltages withopposite polarities from the DC power supply DS2 and the DC power supplyDS3 to the second electrode 262 and the third electrode 263, the chuckmain body 26C is attracted to the dielectric layer 24 and the focus ringFR is attracted to the chuck main body 26C.

In the electrostatic chuck 20 that is any of the electrostatic chucks20A, 20B, and 20C described above, an electrostatic attractive force isgenerated between the chuck main body 26 and the substrate W by applyinga voltage to the first electrode 261. Due to the generated electrostaticattractive force, the substrate W is held on the chuck main body 26. Inaddition, an electrostatic attractive force is generated between thechuck main body 26 and the dielectric layer 24 by applying voltages withopposite polarities to the second electrode 262 and the third electrode263. Due to the generated electrostatic attractive force, the chuck mainbody 26 is attracted to the dielectric layer 24, fixed to the dielectriclayer 24, and fixed to the base 22 via the dielectric layer 24.Therefore, according to the electrostatic chuck 20, the chuck main body26 is fixed to the base 22 without using an adhesive. In a case where atemperature difference occurs between the base 22 and the chuck mainbody 26, the chuck main body 26 can be fixed to the base 22 via thedielectric layer 24 by the electrostatic attractive force, after thetemperature difference between the temperature of the base 22 and thetemperature of the chuck main body 26 is reduced. Therefore, it ispossible to suppress the peeling of the chuck main body 26 and thecracking of the chuck main body 26. In addition, it is possible tosuppress the warpage of the electrostatic chuck 20.

Even if the focus ring FR is attracted to the outer peripheral region260 b of the chuck main body 26 due to residual charges or the like, thefocus ring FR can be detached from the outer peripheral region 260 b ofthe chuck main body 26 by supplying gas to the flow channel 20 f.

Even if the chuck main body 26 is attracted to the dielectric layer 24due to residual charges or the like, the chuck main body 26 can bedetached from the dielectric layer 24 by supplying gas to the flowchannel 20 g.

Hereinafter, embodiments of a method of operating the electrostaticchuck 20 of the plasma processing apparatus 10 will be described. FIGS.11 and 12 are flowcharts showing the method of operating anelectrostatic chuck of a plasma processing apparatus according to anexemplary embodiment. FIGS. 13 and 14 are exemplary timing chartsrelevant to the method shown in FIGS. 11 and 12. In the timing chartsshown in FIGS. 13 and 14, the horizontal axis indicates time. In thetiming charts shown in FIGS. 13 and 14, the vertical axis indicates thevoltage of the first electrode 261, the voltage of the second electrode262 and the voltage of the third electrode 263, the voltage of thefourth electrode 264 and the voltage of the fifth electrode 265, thepressure of the chamber 12 c, the pressure of the back surface of thechuck main body 26, the pressure of the back surface of the focus ringFR, the temperature of the chuck main body 26, and the temperature ofthe base 22.

In the timing charts relevant to the voltage of the first electrode 261in FIGS. 13 and 14, “0” indicates that no voltage is applied to thefirst electrode 261, and “H” indicates that a voltage is applied to thefirst electrode 261. In the timing chart relevant to the voltage of thesecond electrode 262 and the voltage of the third electrode 263, “0”indicates that no voltage is applied to the second electrode 262 and thethird electrode 263, “L” indicates that a voltage having a smallabsolute value is applied to each of the second electrode 262 and thethird electrode 263, and “H” indicates that a voltage having a largeabsolute value is applied to each of the second electrode 262 and thethird electrode 263. In the timing charts relevant to the voltage of thefourth electrode 264 and the voltage of the fifth electrode 265, “0”indicates that no voltage is applied to the fourth electrode 264 and thefifth electrode 265, and “H” indicates that a voltage is applied to eachof the fourth electrode 264 and the fifth electrode 265. In the timingcharts relevant to the pressure of the chamber 12 c, “L” indicates thatthe pressure of the chamber 12 c is low, and “H” indicates that thepressure of the chamber 12 c is high. In the timing charts relevant tothe pressure of the back surface of the chuck main body 26, “L”indicates that the pressure of the back surface of the chuck main body26 is low, and “H” indicates that the pressure of the back surface ofthe chuck main body 26 is high. In the timing charts relevant to thepressure of the back surface of the focus ring FR, “L” indicates thatthe pressure of the back surface of the focus ring FR is low, and “H”indicates that the pressure of the back surface of the focus ring FR ishigh. In the timing charts relevant to the temperature of the chuck mainbody 26, “L” indicates that the temperature of the chuck main body 26 islow, and “H” indicates that the temperature of the chuck main body 26 ishigh. In the timing charts relevant to the temperature of the base 22,“L” indicates that the temperature of the base 22 is low, and “H”indicates that the temperature of the base 22 is high.

A method MT can be executed by controlling each unit of the plasmaprocessing apparatus 10 by the controller Cnt. The method MT can beexecuted in the plasma processing apparatus 10 having the electrostaticchuck 20A or the electrostatic chuck 20B as the electrostatic chuck 20.However, in a case where the application of the voltage to the fourthelectrode 264 and the fifth electrode 265 is not performed independentlyof the application of the voltage to the second electrode 262 and thethird electrode 263, the method MT can also be executed in the plasmaprocessing apparatus 10 having the electrostatic chuck 20C as theelectrostatic chuck 20.

The method MT starts in step ST1. In step ST1, the chuck main body 26 ismounted on the dielectric layer 24, and the focus ring FR is mounted onthe outer peripheral region 260 b of the chuck main body 26. In theexecution period (period from time t1 to time t2 shown in FIG. 13) ofstep ST1, no voltage is applied to each of the first electrode 261, thesecond electrode 262, the third electrode 263, the fourth electrode 264,and the fifth electrode 265. In the execution period of step ST1, thechamber 12 c is not depressurized. Accordingly, the pressure of thechamber 12 c is relatively high. For example, the pressure of thechamber 12 c is set to atmospheric pressure. In the execution period ofstep ST1, the flow channel 20 g and the groove 260 g are notdepressurized by the exhaust device 74. Accordingly the pressure of theback surface of the chuck main body 26 is relatively high. In theexecution period of step ST1, the flow channel 20 f is not depressurizedby the exhaust device 72. Accordingly the pressure of the back surfaceof the focus ring FR is high. In addition, in the execution period ofstep ST1, a low-temperature heat exchange medium is not supplied to theflow channel 22 f. Accordingly, the temperature of the base 22 and thetemperature of the chuck main body 26 are set to relatively hightemperatures.

In subsequent step ST2, the back surface of the chuck main body 26 andthe back surface of the focus ring FR are vacuumed. In the executionperiod (period from time t2 to time t3 shown in FIG. 13) of step ST2, novoltage is applied to each of the first electrode 261, the secondelectrode 262, the third electrode 263, the fourth electrode 264, andthe fifth electrode 265. In the execution period of step ST2, thechamber 12 c is not depressurized. Accordingly, the pressure of thechamber 12 c is relatively high. In the execution period of step ST2,the flow channel 20 g and the groove 260 g are depressurized by theexhaust device 74. Accordingly, the back surface of the chuck main body26 is vacuumed. In the execution period of step ST2, the flow channel 20f is depressurized by the exhaust device 72. Accordingly, the backsurface of the focus ring FR is vacuumed. In addition, in the executionperiod of step ST2, a low-temperature heat exchange medium is notsupplied to the flow channel 22 f. Accordingly, the temperature of thebase 22 and the temperature of the chuck main body 26 are set torelatively high temperatures.

In subsequent step ST3, the passage 12 g is closed by the gate valve 14,and the chamber 12 c is closed. In the execution period (period fromtime t3 to time t4 shown in FIG. 13) of step ST3, no voltage is appliedto each of the first electrode 261, the second electrode 262, the thirdelectrode 263, the fourth electrode 264, and the fifth electrode 265. Inthe execution period of step ST3, the chamber 12 c is not depressurized.Accordingly, the pressure of the chamber 12 c is relatively high. In theexecution period of step ST3, the flow channel 20 g and the groove 260 gare depressurized by the exhaust device 74. In the execution period ofstep ST3, the flow channel 20 f is depressurized by the exhaust device72. In addition, in the execution period of step ST3, a low-temperatureheat exchange medium is not supplied to the flow channel 22 f.Accordingly, the temperature of the base 22 and the temperature of thechuck main body 26 are set to relatively high temperatures.

In subsequent step ST4, the focus ring FR is fixed to the chuck mainbody 26, and the chuck main body 26 is temporarily fixed to the base 22with the dielectric layer 24 interposed therebetween. In the executionperiod (period from time t4 to time t5 shown in FIG. 13) of step ST4, novoltage is applied to the first electrode 261. In the execution periodof step ST4, a voltage whose absolute value is relatively small isapplied from the DC power supply DS2 to the second electrode 262, and avoltage whose absolute value is relatively small is applied from the DCpower supply DS3 to the third electrode 263. Therefore, in the executionperiod of step ST4, the chuck main body 26 is attracted to thedielectric layer 24 by the relatively small electrostatic attractiveforce. In the execution period of step ST4, a voltage is applied fromthe DC power supply DS4 to the fourth electrode 264, and a voltage isapplied from the DC power supply DS5 to the fifth electrode 265.Therefore, an electrostatic attractive force is generated between theouter peripheral region 260 b of the chuck main body 26 and the focusring FR, and the focus ring FR is attracted to the outer peripheralregion 260 b of the chuck main body 26 and fixed to the chuck main body26. In the execution period of step ST4, the chamber 12 c is notdepressurized. Accordingly, the pressure of the chamber 12 c isrelatively high. In the execution period of step ST4, the flow channel20 g and the groove 260 g are depressurized by the exhaust device 74. Inthe execution period of step ST4, the flow channel 20 f is depressurizedby the exhaust device 72. In addition, in the execution period of stepST4, a low-temperature heat exchange medium is not supplied to the flowchannel 22 f. Accordingly, the temperature of the base 22 and thetemperature of the chuck main body 26 are set to relatively hightemperatures.

In subsequent step ST5, the chamber 12 c is depressurized. In theexecution period (period from time t5 to time t6 shown in FIG. 13) ofstep ST5, no voltage is applied to the first electrode 261. In theexecution period of step ST5, continuing from step ST4, a voltage whoseabsolute value is relatively small is applied from the DC power supplyDS2 to the second electrode 262, and a voltage whose absolute value isrelatively small is applied from the DC power supply DS3 to the thirdelectrode 263. In the execution period of step ST5, continuing from stepST4, a voltage is applied from the DC power supply DS4 to the fourthelectrode 264, and a voltage is applied from the DC power supply DS5 tothe fifth electrode 265. In the execution period of step ST5, thechamber 12 c is depressurized by the exhaust device 50. Accordingly, thepressure of the chamber 12 c is set to low pressure. In the executionperiod of step ST5, the flow channel 20 g and the groove 260 g aredepressurized by the exhaust device 74. In the execution period of stepST5, the flow channel 20 f is depressurized by the exhaust device 72. Inaddition, in the execution period of step ST5, a low-temperature heatexchange medium is not supplied to the flow channel 22 f. Accordingly,the temperature of the base 22 and the temperature of the chuck mainbody 26 are set to relatively high temperatures.

In subsequent step ST6, the temperature of the base 22 is adjusted to alow temperature (lowered temperature). In the execution period (periodfrom time t6 to time t7 shown in FIG. 13) of step ST6, no voltage isapplied to the first electrode 261. In the execution period of step ST6,continuing from step ST5, a voltage whose absolute value is relativelysmall is applied from the DC power supply DS2 to the second electrode262, and a voltage whose absolute value is relatively small is appliedfrom the DC power supply DS3 to the third electrode 263. In theexecution period of step ST6, continuing from step ST5, a voltage isapplied from the DC power supply DS4 to the fourth electrode 264, and avoltage is applied from the DC power supply DS5 to the fifth electrode265. In the execution period of step ST6, the chamber 12 c isdepressurized by the exhaust device 50. Accordingly, the pressure of thechamber 12 c is set to low pressure. In the execution period of stepST6, the flow channel 20 g and the groove 260 g are depressurized by theexhaust device 74. In the execution period of step ST6, the flow channel20 f is depressurized by the exhaust device 72. At the start of theexecution period of step ST6, the supply of a low-temperature heatexchange medium to the flow channel 22 f is initiated. Therefore, in theexecution period of step ST6, the temperature of the base 22 quicklydecreases. In addition, in the execution period of step ST6, thetemperature of the chuck main body 26 decreases at a relatively lowspeed. The supply of the low-temperature heat exchange medium to theflow channel 22 f is continued during a period from the start (time t6shown in FIG. 13) of step ST6 to the start (time t21 shown in FIG. 14)of step ST21 to be described later.

In subsequent step ST7, the chuck main body 26 is temporarily attractedto the dielectric layer 24. In the execution period (period from time t7to time t8 shown in FIG. 13) of step ST7, no voltage is applied to thefirst electrode 261. In the execution period of step ST7, a voltage(first voltage) whose absolute value is relatively small is applied fromthe DC power supply DS2 to the second electrode 262, and a voltage(second voltage) whose absolute value is relatively small is appliedfrom the DC power supply DS3 to the third electrode 263. In oneembodiment, in the execution period of step ST7, the first voltage isintermittently applied from the DC power supply DS2 to the secondelectrode 262, and the second voltage is intermittently applied from theDC power supply DS3 to the third electrode 263. For example, theapplication of the first voltage from the DC power supply DS2 to thesecond electrode 262 for several seconds and the stop of the applicationof the voltage to the second electrode 262 for several seconds arealternately performed, and the application of the second voltage fromthe DC power supply DS3 to the third electrode 263 for several secondsand the stop of the application of the voltage to the third electrode263 for several seconds are alternately performed. In the executionperiod of step ST7, continuing from step ST6, a voltage is applied fromthe DC power supply DS4 to the fourth electrode 264, and a voltage isapplied from the DC power supply DS5 to the fifth electrode 265. In theexecution period of step ST7, the chamber 12 c is depressurized by theexhaust device 50. In the execution period of step ST7, the flow channel20 g and the groove 260 g are depressurized by the exhaust device 74. Inthe execution period of step ST7, the flow channel 20 f is depressurizedby the exhaust device 72. In addition, in the execution period of stepST7, continuing from step ST6, a low-temperature heat exchange medium issupplied to the flow channel 22 f.

In the method MT, step STJa is executed during the execution of stepST7. In step STJa, a first determination is made as to whether or notthe temperature difference (first temperature difference) between thetemperature of the base 22 and the temperature of the chuck main body 26is equal to or less than a first predetermined value. The temperature ofthe base 22 is measured by the temperature sensor 77, and thetemperature of the chuck main body 26 is measured by the temperaturesensor 76. The first predetermined value is a value within a range of,for example, 5° C. or more and 10° C. or less. In a case where it isdetermined that the first temperature difference is larger than thefirst predetermined value in step STJa, the execution of step ST7 iscontinued. On the other hand, in a case where it is determined that thefirst temperature difference is equal to or less than the firstpredetermined value in step STJa, step ST8 is executed.

In step ST8, the chuck main body 26 is fixed to the base 22 via thedielectric layer 24. In step ST8, an electrostatic attractive force isgenerated between the dielectric layer 24 and the chuck main body 26 ina state in which the temperature of the base 22 has been adjusted to alowered temperature. In the execution period (period from time t8 totime t9 shown in FIG. 13) of step ST8, no voltage is applied to thefirst electrode 261. In the execution period of step ST8, a voltage(third voltage) whose absolute value is relatively large is applied fromthe DC power supply DS2 to the second electrode 262, and a voltage(fourth voltage) whose absolute value is relatively large is appliedfrom the DC power supply DS3 to the third electrode 263. The absolutevalue of the first voltage is smaller than the absolute value of thethird voltage, and the absolute value of the second voltage is smallerthan the absolute value of the fourth voltage. The application of thethird voltage to the second electrode 262 and the application of thefourth voltage to the third electrode 263 are continued during a periodfrom the start (time t8 shown in FIG. 13) of step ST8 to the start (timet21 shown in FIG. 14) of step ST21 to be described later.

In the execution period of step ST8, continuing from step ST7, a voltageis applied from the DC power supply DS4 to the fourth electrode 264, anda voltage is applied from the DC power supply DS5 to the fifth electrode265. In the execution period of step ST8, the chamber 12 c isdepressurized by the exhaust device 50. In the execution period of stepST8, the flow channel 20 g and the groove 260 g are depressurized by theexhaust device 74. In the execution period of step ST8, the flow channel20 f is depressurized by the exhaust device 72. In addition, in theexecution period of step ST8, continuing from step ST7, alow-temperature heat exchange medium is supplied to the flow channel 22f.

In step subsequent ST9, the substrate W is placed on the substratemounting region 260 a of the chuck main body 26. In the execution period(period from time t9 to time t10 shown in FIG. 13) of step ST9, thepassage 12 g is opened by using the gate valve 14, and the substrate Wis transferred into the chamber 12 c and placed on the substratemounting region 260 a. Then, the passage 12 g is closed by using thegate valve 14, to close the chamber 12 c.

In the execution period of step ST9, no voltage is applied to the firstelectrode 261. In the execution period of step ST9, continuing from stepST8, the third voltage is applied from the DC power supply DS2 to thesecond electrode 262, and the fourth voltage is applied from the DCpower supply DS3 to the third electrode 263. In the execution period ofstep ST9, continuing from step ST8, a voltage is applied from the DCpower supply DS4 to the fourth electrode 264, and a voltage is appliedfrom the DC power supply DS5 to the fifth electrode 265. In theexecution period of step ST9, the chamber 12 c is depressurized by theexhaust device 50. In the execution period of step ST9, the flow channel20 g and the groove 260 g are depressurized by the exhaust device 74. Inthe execution period of step ST9, the flow channel 20 f is depressurizedby the exhaust device 72. In addition, in the execution period of stepST9, continuing from step ST8, a low-temperature heat exchange medium issupplied to the flow channel 22 f.

In subsequent step ST10, the substrate W is fixed to the chuck main body26. In the execution period (period from time t10 to time t11 shown inFIG. 13) of step ST10, a voltage is applied from the DC power supply DS1to the first electrode 261. Therefore, an electrostatic attractive forceis generated between the chuck main body 26 and the substrate W, and thesubstrate W is attracted to the chuck main body 26 and held on the chuckmain body 26. The application of the voltage from the DC power supplyDS1 to the first electrode 261 is continued from the start (time t10shown in FIG. 13) of the execution period of step ST10 to the start(time t12 shown in FIG. 13) of the execution period of step ST12 to bedescribed later.

In the execution period of step ST10, continuing from step ST9, thethird voltage is applied from the DC power supply DS2 to the secondelectrode 262, and the fourth voltage is applied from the DC powersupply DS3 to the third electrode 263. In the execution period of stepST10, continuing from step ST9, a voltage is applied from the DC powersupply DS4 to the fourth electrode 264, and a voltage is applied fromthe DC power supply DS5 to the fifth electrode 265. In the executionperiod of step ST10, the chamber 12 c is depressurized by the exhaustdevice 50. In the execution period of step ST10, the flow channel 20 gand the groove 260 g are depressurized by the exhaust device 74. In theexecution period of step ST10, the flow channel 20 f is depressurized bythe exhaust device 72. In addition, in the execution period of stepST10, continuing from step ST9, a low-temperature heat exchange mediumis supplied to the flow channel 22 f.

In subsequent step ST11, the substrate W is processed. For example, aplasma of a processing gas is generated in the chamber 12 c of theplasma processing apparatus 10, and the substrate W is processed byactive species of molecules or atoms from the plasma. In the executionperiod (period from time t11 to time t12 shown in FIG. 13) of step ST11,continuing from step ST10, a voltage is applied from the DC power supplyDS1 to the first electrode 261. In the execution period of step ST11,continuing from step ST10, the third voltage is applied from the DCpower supply DS2 to the second electrode 262, and the fourth voltage isapplied from the DC power supply DS3 to the third electrode 263. In theexecution period of step ST11, continuing from step ST10, a voltage isapplied from the DC power supply DS4 to the fourth electrode 264, and avoltage is applied from the DC power supply DS5 to the fifth electrode265. In the execution period of step ST11, the chamber 12 c isdepressurized by the exhaust device 50. In the execution period of stepST11, the flow channel 20 g and the groove 260 g are depressurized bythe exhaust device 74. In the execution period of step ST11, the flowchannel 20 f is depressurized by the exhaust device 72. In addition, inthe execution period of step ST11, continuing from step ST10, alow-temperature heat exchange medium is supplied to the flow channel 22f. In a case where the plasma processing is performed, the temperatureof the substrate W, the temperature of the chuck main body 26, and thetemperature of the base 22 increase due to heat input from the plasma.

After the processing on the substrate W is ended, step ST12 is executed.In step ST12, the fixation of the substrate W by the chuck main body 26is released. In the execution period (period from time t12 to time t13shown in FIG. 13) of step ST12, the application of the voltage from theDC power supply DS1 to the first electrode 261 is stopped. In theexecution period of step ST12, continuing from step ST11, the thirdvoltage is applied from the DC power supply DS2 to the second electrode262, and the fourth voltage is applied from the DC power supply DS3 tothe third electrode 263. In the execution period of step ST12,continuing from step ST11, a voltage is applied from the DC power supplyDS4 to the fourth electrode 264, and a voltage is applied from the DCpower supply DS5 to the fifth electrode 265. In the execution period ofstep ST12, the chamber 12 c is depressurized by the exhaust device 50.In the execution period of step ST12, the flow channel 20 g and thegroove 260 g are depressurized by the exhaust device 74. In theexecution period of step ST12, the flow channel 20 f is depressurized bythe exhaust device 72. In addition, in the execution period of stepST12, continuing from step ST11, a low-temperature heat exchange mediumis supplied to the flow channel 22 f.

In subsequent step ST13, the substrate W is transferred out from thechamber 12 c. In the execution period (period starting from time t13shown in FIG. 13) of step ST13, the passage 12 g is opened by using thegate valve 14, and the substrate W is transferred out from the chamber12 c. Then, the passage 12 g is closed by using the gate valve 14.

In the execution period of step ST13, continuing from step ST12, novoltage is applied to the first electrode 261. In the execution periodof step ST13, continuing from step ST12, the third voltage is appliedfrom the DC power supply DS2 to the second electrode 262, and the fourthvoltage is applied from the DC power supply DS3 to the third electrode263. In the execution period of step ST13, continuing from step ST12, avoltage is applied from the DC power supply DS4 to the fourth electrode264, and a voltage is applied from the DC power supply DS5 to the fifthelectrode 265. In the execution period of step ST13, the chamber 12 c isdepressurized by the exhaust device 50. In the execution period of stepST13, the flow channel 20 g and the groove 260 g are depressurized bythe exhaust device 74. In the execution period of step ST13, the flowchannel 20 f is depressurized by the exhaust device 72. In addition, inthe execution period of step ST13, continuing from step ST12, alow-temperature heat exchange medium is supplied to the flow channel 22f. In the method MT, the execution of steps ST9 to ST13 may be repeatedin order to process a plurality of substrates W.

In the method MT, after the execution of step ST13, step ST21 isexecuted first as shown in FIG. 12 in order to maintain the chuck mainbody 26. In step ST21, the fixation of the chuck main body 26 to thebase 22 is released. In the execution period (period from time t21 totime t23 shown in FIG. 14) of step ST21, no voltage is applied to thefirst electrode 261. In the execution period of step ST21, theapplication of the voltage from the DC power supply DS2 to the secondelectrode 262 is stopped, and the application of the voltage from the DCpower supply DS3 to the third electrode 263 is stopped. In the executionperiod of step ST21, continuing from step ST13, a voltage is appliedfrom the DC power supply DS4 to the fourth electrode 264, and a voltageis applied from the DC power supply DS5 to the fifth electrode 265. Inthe execution period of step ST21, the chamber 12 c is depressurized bythe exhaust device 50. In the execution period of step ST21, the flowchannel 20 f is depressurized by the exhaust device 72. In the executionperiod of step ST21, gas from the gas supply unit 73 is supplied to theflow channel 20 g and the groove 260 g. Therefore, the pressure on theback surface of the chuck main body 26 becomes higher than the pressureof the chamber 12 c.

In the method MT, step ST22 is executed after the start (time t21 shownin FIG. 14) of step ST21, so that the temperature of the base 22 isadjusted to a high temperature (increased temperature). In the executionperiod (period from time t21 time t23 in FIG. 14) of step ST23, arelatively high-temperature heat exchange medium can be supplied to theflow channel 22 f of the base 22. The supply of the relativelyhigh-temperature heat exchange medium to the flow channel 22 f maycontinue until the start of step ST26 to be described later.

In subsequent step ST23, the chuck main body 26 is temporarily attractedto the dielectric layer 24 in a state in which the temperature of thebase 22 has been adjusted to an increased temperature. In the executionperiod (period from time t23 to time t24 shown in FIG. 14) of step ST23,no voltage is applied to the first electrode 261. In the executionperiod of step ST23, a voltage (fifth voltage) whose absolute value isrelatively small is applied from the DC power supply DS2 to the secondelectrode 262, and a voltage (sixth voltage) whose absolute value isrelatively small is applied from the DC power supply DS3 to the thirdelectrode 263. In one embodiment, in the execution period of step ST23,the fifth voltage is intermittently applied from the DC power supply DS2to the second electrode 262, and the sixth voltage is intermittentlyapplied from the DC power supply DS3 to the third electrode 263. Forexample, the application of the fifth voltage from the DC power supplyDS2 to the second electrode 262 for several seconds and the stop of theapplication of the voltage to the second electrode 262 for severalseconds are alternately performed, and the application of the sixthvoltage from the DC power supply DS3 to the third electrode 263 forseveral seconds and the stop of the application of the voltage to thethird electrode 263 for several seconds are alternately performed. Theabsolute value of the fifth voltage is smaller than the absolute valueof the third voltage, and the absolute value of the sixth voltage issmaller than the absolute value of the fourth voltage. In the executionperiod of step ST23, continuing from step ST21, a voltage is appliedfrom the DC power supply DS4 to the fourth electrode 264, and a voltageis applied from the DC power supply DS5 to the fifth electrode 265. Inthe execution period of step ST23, the chamber 12 c is depressurized bythe exhaust device 50. In the execution period of step ST23, the flowchannel 20 g and the groove 260 g are depressurized by the exhaustdevice 74. In the execution period of step ST23, the flow channel 20 fis depressurized by the exhaust device 72. In addition, in the executionperiod of step ST23, continuing from step ST22, a high-temperature heatexchange medium is supplied to the flow channel 22 f.

In the method MT, step STJb is executed during the execution of stepST23. In step STJb, a second determination is made as to whether or notthe temperature difference (second temperature difference) between thetemperature of the base 22 and the temperature of the chuck main body 26is equal to or less than a second predetermined value. The temperatureof the base 22 is measured by the temperature sensor 77, and thetemperature of the chuck main body 26 is measured by the temperaturesensor 76. The second predetermined value is a value within a range of,for example, 5° C. or more and 10° C. or less. In a case where it isdetermined that the second temperature difference is larger than thesecond predetermined value in step STJb, the execution of step ST23 iscontinued. On the other hand, in a case where it is determined that thesecond temperature difference is equal to or less than the secondpredetermined value in step STJb, step ST24 is executed.

In step ST24, the application of the voltage to the second electrode 262and the application of the voltage to the third electrode 263 arestopped. The stop of the application of the voltage to the secondelectrode 262 and the stop of the application of the voltage to thethird electrode 263 are continued after the start (time t24 shown inFIG. 14) of the execution period of step ST24. In the execution period(period from time t24 to time t25 shown in FIG. 14) of step ST24, novoltage is applied to the first electrode 261. In the execution periodof step ST24, continuing from step ST23, a voltage is applied from theDC power supply DS4 to the fourth electrode 264, and a voltage isapplied from the DC power supply DS5 to the fifth electrode 265. In theexecution period of step ST24, the chamber 12 c is depressurized by theexhaust device 50. In the execution period of step ST24, gas from thegas supply unit 73 is supplied to the flow channel 20 g and the groove260 g. In the execution period of step ST24, the flow channel 20 f isdepressurized by the exhaust device 72. In addition, in the executionperiod of step ST24, continuing from step ST22, a high-temperature heatexchange medium is supplied to the flow channel 22 f. In step ST24, thefixation of the chuck main body 26 to the base 22 is released.

In subsequent step ST25, the fixation of the focus ring FR to the chuckmain body 26 is released, and the pressure of the chamber 12 c isincreased to, for example, atmospheric pressure. In the execution period(period from time t25 to time t26 shown in FIG. 14) of step ST25, novoltage is applied to the first electrode 261. In the execution periodof step ST25, the application of the voltage to the second electrode 262and the application of the voltage to the third electrode 263 arestopped. In the execution period of step ST25, the application of thevoltage from the DC power supply DS4 to the fourth electrode 264 isstopped, and the application of the voltage from the DC power supply DS5to the fifth electrode 265 is stopped. The stop of the application ofthe voltage from the DC power supply DS4 to the fourth electrode 264 andthe stop of the application of the voltage from the DC power supply DS5to the fifth electrode 265 are continued after the start of theexecution period of step ST25. In the execution period of step ST25, thedepressurization of the chamber 12 c by the exhaust device 50 isstopped. In the execution period of step ST25, gas from the gas supplyunit 73 may or may not be supplied to the flow channel 20 g and thegroove 260 g. In the execution period of step ST25, gas from the gassupply unit 71 can be supplied to the flow channel 20 f. In addition, inthe execution period of step ST25, continuing from step ST24, ahigh-temperature heat exchange medium can be supplied to the flowchannel 22 f.

Subsequent step ST26 starts from time t26 shown in FIG. 14. In stepST26, the chamber 12 c is opened. Accordingly, the pressure of thechamber 12 c is set to atmospheric pressure. Subsequent step ST27 startsfrom time t27 shown in FIG. 14. In step ST27, the chuck main body 26 isdetached, and the maintenance of the chuck main body 26 is performed.

In the method MT, step ST7 is executed in a state in which a largetemperature difference occurs between the temperature of the base 22 andthe temperature of the chuck main body 26. In step ST7, the chuck mainbody 26 is attracted to the dielectric layer 24 with a relatively smallelectrostatic attractive force. As a result, the temperature differencebetween the temperature of the base 22 and the temperature of the chuckmain body 26 is reduced in a state in which the chuck main body 26 isnot completely fixed to the base 22 via the dielectric layer 24. Then,in a case where the temperature difference between the temperature ofthe base 22 and the temperature of the chuck main body 26, that is, thefirst temperature difference becomes equal to or less than the firstpredetermined value, the chuck main body 26 is fixed to the base 22 viathe dielectric layer 24 by the relatively large electrostatic attractiveforce in step ST8. Therefore, damage to the electrostatic chuck 20 andthe malfunction of the electrostatic chuck 20 due to the temperaturedifference between the temperature of the base 22 and the temperature ofthe chuck main body 26 are suppressed.

In step ST7 of the embodiment, the first voltage and the second voltageare intermittently applied to the second electrode 262 and the thirdelectrode 263, respectively. According to the embodiment, damage to theelectrostatic chuck 20 is more reliably suppressed.

In the embodiment, in the case of detaching the chuck main body 26 fromthe base 22 and the dielectric layer 24 for maintenance of the chuckmain body 26, the temperature of the base 22 is increased from theabove-described lowered temperature. In the embodiment, in a case wherethe temperature of the base 22 is adjusted to the increased temperature,the chuck main body 26 is attracted to the dielectric layer 24 with arelatively small electrostatic attractive force in step ST23. As aresult, the temperature difference between the temperature of the base22 and the temperature of the chuck main body 26 is reduced in a statein which the chuck main body 26 is not completely fixed to the base 22via the dielectric layer 24. Then, in a case where the temperaturedifference between the temperature of the base 22 and the temperature ofthe chuck main body 26, that is, the second temperature differencebecomes equal to or less than the second predetermined value, thefixation of the chuck main body 26 to the base 22 is released in stepST24. Therefore, damage to the electrostatic chuck 20 due to thetemperature difference between the temperature of the base 22 and thetemperature of the chuck main body 26 is suppressed. During themaintenance of the chuck main body 26, the chuck main body 26 can beseparated from the base 22 without separating the flow channel 22 f ofthe base 22 for the heat exchange medium from a flow channel (flowchannel provided by the pipe 23 a and the pipe 23 b) for supplying theheat exchange medium to the flow channel 22 f. Therefore, leakage of theheat exchange medium during the maintenance of the chuck main body 26 issuppressed.

In step ST23 of the embodiment, the fifth voltage and the sixth voltageare intermittently applied to the second electrode 262 and the thirdelectrode 263, respectively. According to the embodiment, damage to theelectrostatic chuck 20 is more reliably suppressed.

In the embodiment, gas is supplied to the groove 260 g through the flowchannel 20 g during the execution of at least one of steps ST21 andST24. In the embodiment, even if the chuck main body 26 is attracted tothe dielectric layer 24 due to residual charges or the like, the chuckmain body 26 can be detached from the dielectric layer 24 by supplyinggas to the groove 260 g of the chuck main body 26.

Hereinbefore, various embodiments has been described. However, variousmodifications may be made without being limited to the above-describedembodiments. Although the plasma processing apparatus in the embodimentdescribed above is a capacitively coupled plasma processing apparatus,the plasma processing apparatus including the electrostatic chuckaccording to any of the above-described various embodiments may be anyplasma processing apparatus, such as an inductively coupled plasmaprocessing apparatus and a plasma processing apparatus that generates aplasma using surface waves such as microwaves. In the method MT, anyplasma processing apparatus including the electrostatic chuck accordingto any of the above-described various embodiments can be used.

From the foregoing description, it will be appreciated that variousembodiments of the present disclosure have been described herein forpurposes of illustration, and that various modifications may be madewithout departing from the scope and spirit of the present disclosure.Accordingly, the various embodiments disclosed herein are not intendedto be limiting, with the true scope and spirit being indicated by thefollowing claims.

What is claimed is:
 1. An electrostatic chuck, comprising: a base inwhich a flow channel for a heat exchange medium is provided; adielectric layer provided on the base and fixed to the base; and a chuckmain body mounted on the dielectric layer and configured to hold asubstrate placed thereon with an electrostatic attractive force, whereinthe chuck main body includes: a ceramic main body having a substratemounting region; a first electrode provided in the substrate mountingregion to generate an electrostatic attractive force between a substratemounted on the substrate mounting region and the chuck main body; and asecond electrode and a third electrode forming a bipolar electrode,provided in the ceramic main body, provided between the first electrodeand the dielectric layer to generate an electrostatic attractive forcebetween the chuck main body and the dielectric layer.
 2. Theelectrostatic chuck according to claim 1, wherein the ceramic main bodyfurther provides an outer peripheral region which surrounds thesubstrate mounting region, and on which a focus ring is placed.
 3. Theelectrostatic chuck according to claim 2, wherein the chuck main bodyfurther includes a fourth electrode and a fifth electrode forming abipolar electrode, and the fourth electrode and the fifth electrode areprovided in the outer peripheral region to generate an electrostaticattractive force between the focus ring and the chuck main body.
 4. Theelectrostatic chuck according to claim 3, wherein the fourth electrodeand the fifth electrode are farther from the dielectric layer than thesecond electrode and the third electrode.
 5. The electrostatic chuckaccording to claim 3, wherein the second electrode, the third electrode,the fourth electrode, and the fifth electrode are provided along a sameplane.
 6. The electrostatic chuck according to claim 2, wherein thesecond electrode and the third electrode are provided across thesubstrate mounting region and the outer peripheral region.
 7. Theelectrostatic chuck according to claim 2, wherein a first flow channelthat is opened on a surface of the outer peripheral region on a sideopposite to a side of the dielectric layer is formed in the base, thedielectric layer, and the chuck main body.
 8. The electrostatic chuckaccording to claim 1, wherein the dielectric layer is a ceramic sprayedfilm.
 9. The electrostatic chuck according to claim 1, wherein thedielectric layer is a resin layer bonded directly to the base or bondedto the base with an adhesive layer interposed therebetween.
 10. Theelectrostatic chuck according to claim 1, wherein a groove is providedon a surface of the chuck main body on a side of the dielectric layer ora surface of the dielectric layer on a side of the chuck main body, anda second flow channel connected to the groove is formed in the base andthe dielectric layer.
 11. The electrostatic chuck according to claim 1,further comprising: a first temperature sensor configured to measure atemperature of the base; and a second temperature sensor configured tomeasure a temperature of the chuck main body.
 12. A plasma processingapparatus, comprising: a chamber main body configured for plasmaprocessing; an electrostatic chuck; a radio frequency power supply thatis electrically connected to a base of the electrostatic chuck; a firstDC power supply electrically connected to a first electrode of theelectrostatic chuck; a second DC power supply electrically connected toa second electrode of the electrostatic chuck; and a third DC powersupply electrically connected to a third electrode of the electrostaticchuck, wherein the electrostatic chuck comprises: the base in which aflow channel for a heat exchange medium is provided; a dielectric layerprovided on the base and fixed to the base; and a chuck main bodymounted on the dielectric layer and configured to hold a substrateplaced thereon with an electrostatic attractive force, and wherein thechuck main body includes: a ceramic main body having a substratemounting region; the first electrode provided in the substrate mountingregion to generate an electrostatic attractive force between a substratemounted on the substrate mounting region and the chuck main body; andthe second electrode and the third electrode forming a bipolarelectrode, provided in the ceramic main body, provided between the firstelectrode and the dielectric layer to generate an electrostaticattractive force between the chuck main body and the dielectric layer.13. The plasma processing apparatus according to claim 12, wherein theceramic main body further provides an outer peripheral region whichsurrounds the substrate mounting region, and on which a focus ring isplaced, the chuck main body further has a fourth electrode and a fifthelectrode forming a bipolar electrode, and the fourth electrode and thefifth electrode are provided in the outer peripheral region to generatean electrostatic attractive force between the focus ring and the chuckmain body, and the plasma processing apparatus further comprises afourth DC power supply electrically connected to the fourth electrodeand a fifth DC power supply electrically connected to the fifthelectrode.
 14. The plasma processing apparatus according to claim 12,wherein the ceramic main body further provides an outer peripheralregion which surrounds the substrate mounting region, and on which afocus ring is placed, a first flow channel that is opened on a surfaceof the outer peripheral region on a side opposite to a side of thedielectric layer is formed in the base, the dielectric layer, and thechuck main body, and the plasma processing apparatus further comprises afirst gas supply unit and a first exhaust device that are selectivelyconnected to the first flow channel.
 15. The plasma processing apparatusaccording to claim 14, wherein a groove is provided on a surface of thechuck main body on a side of the dielectric layer or a surface of thedielectric layer on a side of the chuck main body, and a second flowchannel connected to the groove is formed in the base and the dielectriclayer, the plasma processing apparatus further comprises a second gassupply unit and a second exhaust device that are selectively connectedto the second flow channel.